| #include "libm.h" |
| #include <limits.h> |
| |
| #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 |
| int ilogbl(long double x) { |
| return ilogb(x); |
| } |
| #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 |
| int ilogbl(long double x) { |
| PRAGMA_STDC_FENV_ACCESS_ON |
| union ldshape u = {x}; |
| uint64_t m = u.i.m; |
| int e = u.i.se & 0x7fff; |
| |
| if (!e) { |
| if (m == 0) { |
| FORCE_EVAL(0 / 0.0f); |
| return FP_ILOGB0; |
| } |
| /* subnormal x */ |
| for (e = -0x3fff + 1; m >> 63 == 0; e--, m <<= 1) |
| ; |
| return e; |
| } |
| if (e == 0x7fff) { |
| FORCE_EVAL(0 / 0.0f); |
| return m << 1 ? FP_ILOGBNAN : INT_MAX; |
| } |
| return e - 0x3fff; |
| } |
| #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 |
| int ilogbl(long double x) { |
| PRAGMA_STDC_FENV_ACCESS_ON |
| union ldshape u = {x}; |
| int e = u.i.se & 0x7fff; |
| |
| if (!e) { |
| if (x == 0) { |
| FORCE_EVAL(0 / 0.0f); |
| return FP_ILOGB0; |
| } |
| /* subnormal x */ |
| x *= 0x1p120; |
| return ilogbl(x) - 120; |
| } |
| if (e == 0x7fff) { |
| FORCE_EVAL(0 / 0.0f); |
| u.i.se = 0; |
| return u.f ? FP_ILOGBNAN : INT_MAX; |
| } |
| return e - 0x3fff; |
| } |
| #endif |
